Most of the instruments I work with involve spectroscopy which is the study of light that is spread out into the familiar rainbow spectrum. The grass is green and the sky is blue because atoms and molecules absorb and reflect light at specific wavelengths.
If you burn something, the flame gives off different colors. Your gas stove burns blue, but salt will burn yellow. All atoms under the right conditions give off very specific colors of light. If you can measure the light accurately, you can determine which atoms are in the sample. I use lasers to burn specimens, telescopes to collect light from stars and other types of equipment to look at specific wavelengths of light.
I have been involved with various aspects of spectroscopy since 1998. The treck started when I asked the astronomical question "how do you measure redshift?". At that time amateurs had yet to measure redshifts on stars. Maurice Gavin to my knowledge was the first amateur to measure galactic redshifts on quasars.
I started out building a simple spectrograph and using a fiber optic cable to connect it to the telescope. This worked out well and I soon was able to measure stellar redshifts. I contacted Sky and Telescope about doing an article and they turned it down. This motivated me to push the limits of radial velocity measurements which lead to the search for extrasolar planets. Complete info is at www.spectrashift.com and simple explanations in the Astronomy section.
My current lab can now analyze light across the spectrum from x-rays to infrared.